Circuit interrupting apparatus



Feb. 13, 1934. w. E. PAUL CIRCUIT INTERRUPTING APPARATUS Filed Sept. 26. 1929 ILS Aitor-neg.

Pat-eared Feb. 13,1934

i 1,947,224 CIRCUIT INTEBRUPTING APPARATUS William E. Paul, Schenectady, N. Y., assigner tov General Electric Company, a v corporation o! Application September 26, 1929 Serial No.'v 395,412

Claims. (Cl. 20o-150) My invention relates to circuit interrupting apparatus, and more particularly to fluid-break switches having appreciable interrupting capacity, as of the oil type, wherein an arc drawn be- 5 tween the contacts immersed in the insulating I liquid is extinguished by a blast of the insulatingliquid transversely thereof.

A principal object of my invention is the provision of arc extinguishing means for dividing' the arc drawn between the contacts into a plurality of arc sections wherein the pressure de veloped by one of the arcs is utilized for effecting interruption of one of the other arcs.

A further object of my invention is the proopening movement of the switch so as to eiect a blast of insulating or arc extinguishing fluid transversely of another arc immediately upon its formation subsequent to the initial arc.

A further object of my invention is the provision of means for absorbing excess energy developed by the initial arc and for subsequently releasing or returning this energy to aid in the projection of insulating iluid transversely across the other arc. l My invention will be more fully set forth in the following description referring to the accompanying drawing, and the features of novelty which characterize my invention willbe pointed out with particularity in the claims annexed to and forming a part of this specication. Referring to the drawing, Fig. 1 is an elevational view, partly in section; of. a fluid-break 85 switch embodying my invention; Fig. 2 is an enlarged view, partly in section, of apparatus illustrated in-Fig. 1, and Figs. 3 and 4 are views, partly in section, further illustrating, the arrangement of elements shown in Fig. 2.

Referring to Fig. 1 of the drawing, there is illustrated a duid-break switchv comprising a movable bridging member 1, having mounted at its opposite ends thecontact rods 2 and 3. The contact rods 2 and 3 are guided by the bushing :c5 members 4 and 5 for central longitudinal movement with respect to the cylindrical housing structures -6 and 'I which may be of conducting material and electrically connected to the usual lead-in conductor studs 8 and 9. Mounted within and at the lower end of each of the housings 6 and 7 is a stationary contact 10 adapted to receive and electrically contact with its cooperating rod contact when the same has been moved to its lower circuit closingposition by the bridging 55 member l. The main current carrying movable contacts l1 and 12 are mounted on the bridging member 1 to coact with the' stationary contacts 1K3 and '14 in a well-known manner. 1

xSpaced a short distance above the fixed contact 10 is an insulating partition .15 provided 0 with a slot 16 through which the contact rod 2 may extend. The slot 16 furthermore serves to guide a pair of metallic conducting members 17 and 18 which are resiliently biased, as by the springs 19 and 20, towards each other in the 65 manner of a trap-door for a purpose hereinafter described. The members 17 and 18 are insulated with respect to the housing 6 as best illustrated in Fig. 1, the springs 19 and 20 bearing against insulating projections 19 and 20 respectively 70 forming part of the insulation partition `15.

Referring more particularly to Fig. 2, the partition 15 is likewise provided with an aperture o1' opening 21, thereby permitting communication between a. lower chamber in which the stationary contact is disposed and the space above the partition 15. Ay second partition member 22- is spaced from and disposed above the partition 15 tol form a second chamber, and is provided with 'a central opening for receiving the lower 80 end of the insulating guide or sleeve 23 within which the movable contact rod 2 is disposed. The partition 22 permits communication between the second chamber and the space above said partition byV means of an aperture 24. B5

` ,In the apparatus so far described it will be apparent that the initial opening movement of the contact rod 2, which in its closed circuit position extends between and electrically contacts with the oppositely biased conducting members 17 and 18, is effective to draw an arc between the stationary contact 10 and the movable con- A tact. Since a normal level of the insulating fluid,

such as oil, will be maintained approximately at the level indicated in 1, there will be the usual formation of gases by the action of the arc on the oil with consequent rapid increase in pressure. As the movable contact moves upwardly .and remains in engagement with the conducting members 17 and 18 the arc persists and is 100 transferred to the said conducting members as the contact rod moves out of the lower chamber. During this interval the initial arc drawn from the stationary contact l0 is developing increasingly higher pressures which are communicated to the second or upper chamber by reason of the aperture 21 in the partition 15. Accordingly,

when the contact rod in continuing this opening A movement is withdrawn from the conducting members 17 and 18 permitting them to be biased 110 towards and engage each other as illustrated; a second arc, hereinafter referred to as the main are, will be drawn between the conducting members and the contact rod. The opening 24 in the partition 22 exhausts at a comparatively` lov.1 pressure into the upper part of the housing 6, so that the 'pressure developed by the initial arc is eiective to direct a cooling stream, or blast, of the insulating iiuid transversely of and across the main arc immediately upon formation thereof and upwardly through aperture 24 into the` low pressure space. In view of the fact that a cooling stream of fresh dielectric would be directed across the main arc as loug as the pressure in the lower chamber exists, it will be apparent that rupture of the main arc is directly assisted by the existence of the initial arc which may be comparatively short and is fixed in length.

Since the pressure developed in the lower chamber by the initial arc may increase so rapidly and to such proportions that damage to the apparatus might result if means for relieving this high, sudden pressure is not available, there are provided expansion or pressure relief chambers 25 and 26 mounted above the partition 22 and extending through the same and the partition 15 to communicate directly with the lower chamber. As illustrated in Figs. 2 and 3, each compression chamber comprises a piston-like element 27, normally biased by a spring 28 to seat at the* lower end of the chamber. Vents 29 in the upper part of the chambers may be provided, if desired. Accordingly, excessive pressure developed in the lower chamber may be temporarily relieved or stored within the expansion chambers 25 and 26 by reason of the compression of the springs and the air cushion at the upper end of the chambers. When the initial force of the arc has diminished the expansion chambers operate to return part oi this excess energy to the lower chamber, thereby tending to maintain suiicient pressure therein for directing a continued blast of the insulatingor arc extinguishing fluid across the main arc.

The operation of the complete apparatus is as follows:

Assuming that the contact rods 2 and 3 are in engagement with their co-operating contacts, the initial upward or opening movement of the bridging member 1 will be effective to draw an initial arc between a contact 10 and its movable contact member. As previously described, a sudden high pressure is developed within the lower chamber arc between the trap-door andthe contact rod as sustained by the energy which has returned from the expansion chambers, causes a strong blast of the insulating nuid to be directed across the main arc within the upper chamber, and to exhaust by way of aperture 24 into the upper part o1' the housing. In viewoi the fact that the arcs are in series, rupture of either one of them is effective vto interrupt the current and it follows, therefore, that so long as the initial arc exists there will be pressure developed in the lower chamber tending to continue the stream of cooling insulating fluid across the main arc. Furthermore, since there will be a certain time element in storing and returning the energy in and from the expansion chambers 25 and 26, the additional energy available therefrom will be eiective to aid and sustain the ow of the insulating :duid at a time when it is most needed, namely, when the initial explosive effect of the initial arc has been spent.

For the purpose of clearness in illustration, the chamber within which the main arc occurs is shown as simply as possible. In actual practice, however, it may be desirable to connue the ilow of the insulating fluid across the main arc within a channel-like passage, which may be formed in any suitable manner, as by iilling in the spaces l between the upper and lower walls of the chamber on opposite sides of the channel, the channel of course communicating in the previously described manner with the chambers above and below the same. i

It shall be understood that my invention is not limited to the specic construction herein illustrated and described but is adapted for use with different types of huid-break switches, as for example, the type wherein the movable contactsl may move downwardly instead of upwardly with respect to their co-operating stationary contacts.

What I claim as new and desire to secure by Letters Patent of the United States, is:-

1. Circuit interrupting apparatus comprising l stationary and movable contacts, an insulating partition through which the movable contact is withdrawn from the stationary contact, said partition deiining upper and lower chambers in one of which the stationary contact is mounted, metallic conducting means resiliently biased so as to close the opening in said partition through which the movable contact is withdrawn subsequent to said withdrawal, and means directing the pressure developed by the initial part of the arc in e stationary contact chamber to efl'ect a blast of extinguishing fluid from the last-named chamber across the arc between said metallic closing means and the movable contact in the other chamber.

2. In a fluid-break switch, arc-interrupting means comprising a casing, a partition dividing the casing into chambers, a fixed contact disposed in one oi said chambers, a coacting movable contact adapted to be withdrawn through said partition lto its open position, and metallic closure members normally biased to a position covering the opening in said partition through which-the movable contact is withdrawn, said closure members covering said opening subsequent to withdrawal of the movable contact thereby dividing the arc into sections, said partition being provided with an aperture so that the pressure due to arcing between the iixed contact and metallic of arc extinguishing iiuid from. the fixed contact chamber transversely through the other chamber and across the arc formed between said closure members and the movable contact.

closure members is effective to direct a blast 3.111 a fluid-break switch, arc interrupting 150 means comprisinga casing, a partition dividing the casing into chambers, a nxed contact disposed in one oi' said chambers, a coacting movable contact adapted to be withdrawn through said partition to its open position, and a pair ot members o i' conducting material normally biased towards each other to close the opening in the partition through which the movable contact is withdrawn whereby the arc drawn between the separating contact is divided into sections, said .partition having anaperture permitting uid communicaon between the ilxed contact'chamber and a second chamber, said second chamber having an exhaust opening arranged so that the pressure developed by the arc in said xed contact chamber is effective to force a stream o! insulating fluid transversely across the arc in said second chambers prior to ow throughsaid exhaust opening.

'4. In an electric .circuit-interrupter, in combination, a pressure chamber containing an arc extinguishing liquid, means forming a pressure generating arc within said'chamber, means directing an arc-extinguishing blast of said liquid` from said chamber, and an expansion chamber including a piston biased in. opposition to pressure in said "chamber in communication with saidY lpressure chamber for storing energy generated by said arc, said stored energy sustaining said blast o! insulating` liquid.

5. In a fluid-break switch, arc-interrupting means comprising a casing, an insulating partition dividing said casing into upper and lower chambers, astationary contact disposed in the llower-chamber, acoacting movable rod contact adapted to be withdrawn through an opening inthe partition and into said upper chamber, conducting closure means adapted to close said opening after the movable contact is withdrawn wherespring-biased piston in communication with the `in the upper chamber.r

by the arc drawn between the contacts isdivided into sections within said chambers res c tively, and an expansion chamber includ a c.4 In a nuidsbreak switch, am extinguishing apparatus comprising a casing, relatively mov- J'able contacts therein, aninsulating structure dividing said casing into chambers, said structure having an opening for separation of said contacts within said chambers, and conducting gate meml bers mounted on said structure operable to close said opening during separation of said contacts dividing the resulting arc `into sections within said chambers respectively, said structure likewise having apertures other than said opening for` directing a blast of insulating liquid'from one ofv said chambers and transverselyracross a main arcfin anotherchamber'prior to exhaust from said last-named chamber.

across the arc formed in the other chamber prior tol exhaust Afrom said lastgnamed chamber.

8. An electric circuit interrupter comprising a casing including insulating structure forming chambers therein, a pair of relatively movable contactsiarranged to separate within said casing so as to drawan arc successively through said chambers, means partially cpnning the pressure generated by an initial part of the arc in one of said chambers, and Ymeans directing said pressure so as to cause a blast of arc extinguishing liquid from said last-named chamber through and transversely of a second chamber to exhaust from said second chamber, said blast traversing completely theY arc in said second chamber prior to exhaust therefrom.

9. An electric circuit interrupter comprising a casing including insulating structure forming a plurality of interconnecting chambers therein, a fixed contact mounted within one ot said chambers, a movable rodcontact coacting with said fixed contact so as to draw,an arc successively through said chambers upon opening' of the circuit, means partially conti/ning the arcing pressure within said iixed contact chamber upon initial separation of said contacts and means directing said pressure so as to cause a blast oi' arc-extinguishing liquid from said xed contact chamber through and transversely of a second chamber adjacent thereto to exhaust from said chamber, said blast traversing completely the.

spectively, and means directing the arcing pres-l 'sure within said iixed contact chamber so as to cause a'blastf arc-extinguishingliquid therefrom through and transversely of said adjacent f. chamberto exhaust from said chamber, said. blast i.

traversing completely the arc in said adjacent chamber prior to exhaust therefrom. 

